This invention relates to knee braces and more particularly comprises an improved knee brace for controlling ligament instability in all planes.
When the ligaments surrounding the knee have been traumatized by injury or by surgery, a supporting brace is used to provide stability while allowing movement of the knee. The brace should provide stability against forces applied in the medial and lateral side planes and in the anterior and posterior planes. Further, the brace should provide rotational stability so as to prevent excessive rotation of the tibia in relation to the femur. The brace should also inhibit pivot shift (forward displacement of the tibia) by preventing the knee from achieving a full extension.
A known knee brace for controlling ligament instability includes a shin plate and a thigh plate connected in hinged relationship. The shin plate has a circular interior surface and is held on the shin by a wide calf band extending around the back of the leg at mid-calf. A pair of straps which criss-cross behind the back of the knee extend between opposing flanges on the top corners of the shin plate and points on the opposing sides of the thigh plate. An extension check strap, attached at opposing ends to opposing sides of the thigh plate, is looped around the calf band.
The known knee brace has numerous disadvantages. Principally, it fails to fully control ligament instability because it is not securely fastened to the leg. Further, the brace is uncomfortable and restrictive in that the cross straps behind the knee cause excessive chafing and their bulkiness behind the knee interferes with movement of the leg. The looping of the extension check strap around the calf band causes further abrasion and bulkiness behind the calf. The interior of the shin plate tends to press on the crest of the tibia bone and cause excessive abrasion.
It is an object of the invention to provide a knee brace which fully controls ligament instability while allowing natural action of the knee and which is both comfortable to wear and capable of being securely fastened to the leg.